A Geospatial Analysis of the Impact of Landuse On Potential Loadings of Nonpoint Source Pollutants to Surface Waters.

Recently, the Chesapeake Bay has been scrutinized for poor water quality, including high levels of nitrogen and phosphorus, large algae blooms, low levels of dissolved oxygen, and increased turbidity. Land use contributes to nutrient and sediment loadings to the Bay. The effect of land use on potential nutrient loadings from a smaller sub-watershed can be determined and analyzed with computer models. The Sassafras River watershed, a sub-watershed on the Eastern shore of Maryland, was selected as a study site. The objective of this research was to use the GLEAMS model to simulate how agricultural management practices affect potential nutrient loadings on non-tidal streams in the Sassafras River watershed.  The GLEAMS-NAPRA model was used to simulate nitrogen, phosphorus and sediment dynamics. Soil data was found in the STATSGO Soil Survey and chemical use and planting information was obtained from the GLEAMS internal databases and University of Maryland publications. A three crop rotation of corn, winter wheat, and soybeans was simulated using different conservation practices. The outputs were loaded into hydrology, erosion, plant growth, and nutrient files then imported into Microsoft Excel and analyzed. Rainfall variation among years affected the amount of runoff and possible loadings. Years with higher precipitation amounts generally had higher nutrient and sediment loadings. The GLEAMS model appears to be suited as an environmental planning tool because the effects of management practices, geographical location, and ecological toxicity can be simulated. The project described was supported by Delaware EPSCoR, through National Science Foundation Grant EPS-0447610 and Wesley College.